DistOS 2015W Session 4: Difference between revisions

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= Amebo Operating System =
= Amoeba Operating System =


=== Capablities: ===
=== Capablities: ===

Revision as of 03:21, 30 January 2015

Amoeba Operating System

Capablities:

  • Pointer to the object
  • Capability assigning right to perform to some operation to the object ticket
  • Communicate wide area network
  • a kind of ticket or key that allows the holder of the capa- bility to perform some (not neces- sarily all)
  • Each user process owns some collection of capabilities, which together define the set of objects it may access and the types of operations that my ne performed on each
  • After the server has performed the operation, it sends back a reply message that unblocks the client
  • Sending messages, blocking and accepting forms the remote procedure call that can be encapsulate using to make entire remote operation look like local procedure
  • Second field: used by the sever to identify which of its objects is being addressed server port and object number identify object which operation to performed
  • Generates 48-bit random number
  • The third field is the right field which contains a bit map telling which operation the holder of the capability may performed


Thread Management:

  • Same process have multiple thread and each process has its own registered counter and stack
  • Behave like process
  • It can synchronized using mutex semaphore
  • File: Multiple thread,
  • Blocked when there's multiple threads
  • Buttlet thread the mutex
  • The careful reader may have noticed that user process can pull 813kbytes/sec


The V Distributed System

  • First tent in V design: High Performance communication is the most critical facility for distributed systems.
  • Second; The protocols, not the software, define the system.
  • Third; a relatively small operating system kernel can implement the basic protocols and services providing a simple network-transparent process, address space & communication model.

Ideas that significantly affected the design

  • Shared Memory.
  • Dealing with group of entities same as they deal w/individual entities.
  • Efficient file caching mechanism using the virtual memory caching mechanism.

Design Decisions

  • Designed for a cluster of workstations with high speed network access ( only really supports LAN ).
  • Abstract the physical architecture of the participating workstations, by defining common protocols providing well-defined interfaces.